Display device and manufacturing method thereof

ABSTRACT

A display device includes a display region including light emitting elements; a first inorganic insulating layer covering the light emitting elements; a first organic insulating layer on the first inorganic insulating layer; a second organic insulating layer on the first organic insulating layer; a third organic insulating layer on the second organic insulating layer; and a second inorganic insulating layer on the third organic insulating layer. Edges of the first to third organic insulating layers are between edges of the first and second inorganic insulating layers and an edge of the display region; the edge of the second organic insulating layer is between the edge of the first organic insulating layer and the edge of the display region; and the edge of the third organic insulating layer is between the edges of the first and second inorganic insulating layers and the edge of the second organic insulating layer.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromthe prior Japanese Patent Application No. 2016-134746, filed on Jul. 7,2016, the entire contents of which are incorporated herein by reference.

FIELD

An embodiment according to the present invention relates to a displaydevice, and a method for manufacturing the same.

BACKGROUND

As display devices usable for electric appliances and electronicdevices, a liquid crystal display device using an electro-optical effectof a liquid crystal material and an organic EL (electroluminescence)display device including an organic electroluminescence (EL) elementhave been developed. Such a display device includes a display screenformed of a plurality of pixels provided on a substrate. Each of theplurality of pixels of the display device includes a liquid crystalelement, an organic electroluminescence element or the like as a displayelement. In the display device, such pixels arrayed in a display regionare driven by a pixel circuit and a driving circuit each including atransistor, and thus a signal is input and a moving image or a stillimage is displayed.

In the case where an organic EL element is used as the display element,a sealing layer is provided so as to cover an organic light emittinglayer. For example, Japanese Laid-Open Patent Publication No.2016-046126 discloses that such a sealing layer prevents permeation ofmoisture or oxygen into an organic light emitting layer.

In the meantime, a touch panel, which is a display device including adisplay element and a touch sensor provided on the display element, hasbeen rapidly spread recently. Such a touch panel is now indispensablefor mobile information terminals such as smartphones and the like, andis progressively developed worldwide for further improvement in theinformation society.

Methods for manufacturing such a touch panel are classified into twosystems: one is an out-cell system, by which a touch sensor ismanufactured separately from a display device and then the touch sensorand the display device are bonded together, and the other is an in-cellsystem, by which a touch panel is incorporated into a display device.

SUMMARY

An embodiment according to the present invention provides a displaydevice including a display region including a plurality of lightemitting elements arrayed in a matrix; a first inorganic insulatinglayer provided so as to cover the plurality of light emitting elements;a first organic insulating layer provided on the first inorganicinsulating layer; a second organic insulating layer provided on thefirst organic insulating layer; a third organic insulating layerprovided on the second organic insulating layer; and a second inorganicinsulating layer provided on the third organic insulating layer. An edgeof each of the first to third organic insulating layers is locatedbetween edges of the first inorganic insulating layer and the secondinorganic insulating layer and an edge of the display region; the edgeof the second organic insulating layer is located between the edge ofthe first organic insulating layer and the edge of the display region;the edge of the third organic insulating layer is located between theedges of the first inorganic insulating layer and the second inorganicinsulating layer and the edge of the second organic insulating layer;and the edges of the first inorganic insulating layer and the secondinorganic insulating layer are located outer to the edge of the displayregion and the edges of the first to third organic insulating layers.

BRIEF EXPLANATION OF DRAWINGS

FIG. 1A is a plan view showing a structure of a display device in anembodiment according to the present invention;

FIG. 1B is a plan view showing a structure of a part of the displaydevice in an embodiment according to the present invention;

FIG. 1C is a cross-sectional view showing a structure of the displaydevice in an embodiment according to the present invention;

FIG. 2A and FIG. 2B are each a cross-sectional view showing a structureof the display device in an embodiment according to the presentinvention;

FIG. 3A is a cross-sectional view showing a structure of the displaydevice in an embodiment according to the present invention;

FIG. 3B is a plan view showing a structure of the display device in anembodiment according to the present invention;

FIG. 4A is a cross-sectional view showing a structure of the displaydevice in an embodiment according to the present invention;

FIG. 4B is a plan view showing a structure of the display device in anembodiment according to the present invention;

FIG. 5A is a cross-sectional view showing a method for manufacturing thedisplay device in an embodiment according to the present invention;

FIG. 5B is a plan view showing the method for manufacturing the displaydevice in an embodiment according to the present invention;

FIG. 6A is a cross-sectional view showing the method for manufacturingthe display device in an embodiment according to the present invention;

FIG. 6B is a plan view showing the method for manufacturing the displaydevice in an embodiment according to the present invention;

FIG. 7A is a cross-sectional view showing the method for manufacturingthe display device in an embodiment according to the present invention;

FIG. 7B is a plan view showing the method for manufacturing the displaydevice in an embodiment according to the present invention;

FIG. 8A is a cross-sectional view showing the method for manufacturingthe display device in an embodiment according to the present invention;

FIG. 8B is a plan view showing the method for manufacturing the displaydevice in an embodiment according to the present invention;

FIG. 9A is a cross-sectional view showing the method for manufacturingthe display device in an embodiment according to the present invention;

FIG. 9B is a plan view showing the method for manufacturing the displaydevice in an embodiment according to the present invention;

FIG. 10A is a cross-sectional view showing the method for manufacturingthe display device in an embodiment according to the present invention;

FIG. 10B is a plan view showing the method for manufacturing the displaydevice in an embodiment according to the present invention;

FIG. 11A is a cross-sectional view showing the method for manufacturingthe display device in an embodiment according to the present invention;

FIG. 11B is a plan view showing the method for manufacturing the displaydevice in an embodiment according to the present invention;

FIG. 12 is a cross-sectional view showing a structure of the displaydevice in an embodiment according to the present invention;

FIG. 13 is a cross-sectional view showing a structure of the displaydevice in an embodiment according to the present invention;

FIG. 14 is a cross-sectional view showing the method for manufacturingthe display device in an embodiment according to the present invention;

FIG. 15 is a cross-sectional view showing the method for manufacturingthe display device in an embodiment according to the present invention;

FIG. 16 is a cross-sectional view showing the method for manufacturingthe display device in an embodiment according to the present invention;and

FIG. 17 is a cross-sectional view showing the method for manufacturingthe display device in an embodiment according to the present invention.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments according to the present invention will bedescribed with reference to the drawings. The present invention may becarried out in any of various forms and should not be construed as beinglimited to any of the following embodiments. In the drawings, componentsmay be shown schematically regarding the width, thickness, shape and thelike, instead of being shown in accordance with the actual sizes, forthe sake of clearer illustration. The drawings are merely examples anddo not limit the interpretations of the present invention in any way. Inthe specification and the drawings, components that have substantiallythe same functions as those described before with reference to aprevious drawing(s) bear the identical reference signs thereto (oridentical numerals with “a”, “b” or the like provided after thenumerals), and detailed descriptions thereof may be omitted. The words“first”, “second” or the like provided for components are used merely todistinguish the components from each other, and do not have any furthermeaning unless otherwise specified.

In the specification and the claims, an expression that a component or aregion is “on” another component or region encompasses a case where sucha component or region is in direct contact with the another component orregion and also a case where such a component is above or below theanother component or region, namely, a case where still anothercomponent or region is provided between such a component or region andthe another component or region, unless otherwise specified. In thefollowing description, the terms “above”, “up” and the like refer to theside on which a second substrate is provided with respect to a substrate(substrate generally referred to as the “substrate 100”), and the terms“below”, “down” and the like refer to the opposite side.

In this specification, the substrate at least includes one main surfacethat is planar. On the one main surface, layers including asemiconductor layer and a conductive layer, and components including atransistor and a display element, are provided. A description providedbelow regarding a cross-section is made with respect to the one mainsurface of the substrate. The terms “up”, “upper layer”, “above” and“upper surface” are used with respect to the one main surface of thesubstrate.

In this specification, the terms “film” and “layer” have substantiallythe same meaning, and may be used interchangeably optionally. Forexample, an element referred to as a “conductive layer” may also bereferred to as a “conductive film”.

In this specification, the expression that “A and B are connected witheach other” encompasses a case where A and B are directly connected witheach other physically, and also a case where A and B are electricallyconnected with each other. The expression that “A and B are electricallyconnected with each other” indicates that in the case where an itemperforming an electric action exists between A and B, the item allows anelectric signal to be transferred between A and B.

Any other term that would be appreciated by a person of ordinary skillin the art will not be specifically explained.

In a display device including an organic EL element, a sealing layer hasa higher effect as being thicker, and improves the long-term reliabilityof the display device. However, in the case where a line layer used fora touch sensor is formed on the organic EL element, a thick sealinglayer may cause the line layer to be broken at a step provided by thesealing layer and thus may cause line disconnection.

An embodiment according to the present invention described belowprovides a display device including a touch panel provided on a displayelement with no line disconnection. An embodiment according to thepresent invention provides a highly reliable display device.

(Embodiment 1, Display Device Structure 1)

FIG. 1A is a plan view of a display device 10.

As shown in FIG. 1A, the display device 10 includes a substrate 100, asubstrate 101, a display region 103 including pixel 102, a peripheralregion 104, a touch sensor 105, a driving circuit 106 having a functionof a source driver, a driving circuit 107 having a function of a gatedriver, and a flexible printed circuit board 108. As shown in FIG. 1A,the pixel 102 are arrayed in a matrix, and lines for the touch panel 105extend in a row direction and a column direction. Further, as shown inFIG. 12 or the like, the pixel 102 includes a display element 130.Therefore, a plurality of display elements 130 are also arranged in amatrix.

In the display device 10, the display region 103, the driving circuit106, the driving circuit 107, and the flexible printed circuit board 108are electrically connected with each other. A signal is input from anexternal device, and a still image or a moving image is displayed. Thetouch sensor 105 is electrically connected with the flexible printedcircuit board 108. Information is input and output by, for example, anelectrostatic capacitance system, which uses a change in the inter-linecapacitance at the time of contacting the touch sensor 105.

The structure, method or the like described in embodiment 1 may beappropriately combined with a structure, method or the like shown in anyother embodiment.

(Embodiment 2, Structure of the Peripheral Region of the Display Device)

FIG. 1B is an enlarged view of a region 20 in the display device 10shown in FIG. 1A. The region 20 includes a part of the display region103, a part of the peripheral region 104, a part of a conductive layer171, and a part of a sealing member 173. In the display device 10, theperipheral region 104 is outer to an edge of the display region 103.

FIG. 1C is a cross-sectional view taken along line A1-A2 in FIG. 1B. Asshown in FIG. 1C, the peripheral region 104 includes a conductive layer160, a sealing layer 161, the conductive layer 171, the sealing member173, a filling member 174, and the substrate 101. The conductive layer160 is usable as an electrode of a light emitting element 130 includedin the display region 103. The substrate 100 and the substrate 101 maybe secured to each other by the sealing member 173 so as to provide ahollow structure without the filling member 174. Alternatively, in thecase where the substrate 100 and the substrate 101 may be secured toeach other by the filling member 174, the sealing member 173 may beomitted.

The sealing layer 161 includes an inorganic sealing layer 162, anorganic sealing layer 163, an organic sealing layer 165, an organicsealing layer 167, and an inorganic sealing layer 169. The sealing layer161 has a function of preventing permeation of moisture or oxygen into alight emitting element such as an organic EL layer or the like. Thesealing layer 161 is provided so as to cover the display region 103.

The inorganic sealing layer 162 and the inorganic sealing layer 169 mayeach be formed of an insulating film containing at least one of aluminumoxide, magnesium oxide, silicon oxide, silicon oxide nitride, siliconnitride oxide, silicon nitride, gallium oxide, zirconium oxide,lanthanum oxide, neodymium oxide, hafnium oxide and tantalum oxide. Theinorganic sealing layer 162 and the inorganic sealing layer 169 may eachhave a thickness of several ten nanometers to several micrometers.

The organic sealing layer 163, the organic sealing layer 165 and theorganic sealing layer 167 may each be formed of acrylic resin, polyimideresin, epoxy resin or the like. The organic sealing layer 163, theorganic sealing layer 165 and the organic sealing layer 167 may eachhave a thickness of several micrometers to several ten micrometers.

The sealing layer 161 has the following structure. The organic sealinglayer 163 is provided on the inorganic sealing layer 162. The organicsealing layer 165 is provided on the organic sealing layer 163. Theorganic sealing layer 167 is provided on the inorganic sealing layer162, the organic sealing layer 163 and the organic sealing layer 165.The inorganic sealing layer 169 is provided on the inorganic sealinglayer 162 and the organic sealing layer 167.

Edges of the organic sealing layer 163, the organic sealing layer 165and the organic sealing layer 167 are located between edges of theinorganic sealing layer 162 and the inorganic sealing layer 169 and anedge of the display region 103.

The edge of the organic sealing layer 165 is located between the edge ofthe display region 103 and the edge of the organic sealing layer 163.The edge of the organic sealing layer 167 is located between the edgesof the inorganic sealing layer 162 and the inorganic sealing layer 169and the edge of the organic sealing layer 163.

The edges of the inorganic sealing layer 162 and the inorganic sealinglayer 169 are located outer to any of the edges of the display region103, the organic sealing layer 163, the organic sealing layer 165 andthe organic sealing layer 167.

With the above-described structure, the inorganic sealing layer 162 andthe inorganic sealing layer 169 are in contact with each other. Thisprevents the edges of the organic sealing layer 163, the organic sealinglayer 165 and the organic sealing layer 167 from being exposed outside.There are a plurality of the inorganic sealing layers. Therefore, evenif a defect such as a pin hole or the like is formed in a part of theinorganic sealing layers, the other inorganic sealing layers compensatefor the defect and thus permeation of moisture is suppressed moreeffectively.

As shown in FIG. 2A, the sealing layer 161 may further include aninorganic sealing layer 164 provided between the organic sealing layer163 and the organic sealing layer 165, and include an inorganic sealinglayer 166 provided between the organic sealing layer 165 and the organicsealing layer 167. In this case, as shown in FIG. 2B, the edge of theorganic sealing layer 167 may be provided between the edge of thedisplay region 103 and the edge of the organic sealing layer 165.

FIG. 3A and FIG. 4A are each a cross-sectional view of the displaydevice 10 taken along line A1-A2 shown in FIG. 1B. FIG. 3A and FIG. 4Bare each a plan view of the display device 10 in an area correspondingto the edges of the organic sealing layer 163, the organic sealing layer165 and the organic sealing layer 167 and the vicinity thereof. Theconductive layer 171 may be wider in an area thereof overlapping theedges of the organic sealing layer 163, the organic sealing layer 165and the organic sealing layer 167 than in the remaining area.Alternatively, as shown in FIG. 4B, the conductive layer 171 may have alinear shape.

As seen in the cross-sectional view taken along line A1-A2, it ispreferable that the edges of the organic sealing layer 163, the organicsealing layer 165 and the organic sealing layer 167 are tapered, namely,inclined.

As seen in the cross-sectional view taken along line A1-A2, it ispreferable that the edges of the organic sealing layer 163, the organicsealing layer 165 and the organic sealing layer 167 each have a roundedcorner as shown in, for example, FIG. 12.

The above-described structure allows the conductive layer 160 to beprovided stably with no line disconnection.

(Embodiment 3, Method for Manufacturing the Peripheral Region of theDisplay Device)

Hereinafter, a method for manufacturing the display device in anembodiment according to the present invention with reference to FIG. 5A,FIG. 5B, FIG. 6A, FIG. 6B, FIG. 7A, FIG. 7B, FIG. 8A, FIG. 8B, FIG. 9A,FIG. 9B, FIG. 10A, FIG. 10B, FIG. 11A and FIG. 11B. The display devicemanufactured by the following method corresponds to the display device10 shown in FIG. 1A, FIG. 1B, FIG. 1C, FIG. 2A, FIG. 2B, FIG. 3A, FIG.3B, FIG. 4A and FIG. 4B. FIG. 5A, FIG. 6A, FIG. 7A, FIG. 8A, FIG. 9A,FIG. 10A and FIG. 11A are each a cross-sectional view showing each ofsteps of the method for manufacturing the display device 10. FIG. 5B,FIG. 6B, FIG. 7B, FIG. 8B, FIG. 9B, FIG. 10B and FIG. 11B are each aplan view showing each of the steps of the method for manufacturing thedisplay device 10.

On the conductive 160, the inorganic sealing layer 162 is formed (seeFIG. 5A and FIG. 5B). In this step, it is preferable that the inorganicsealing layer 162 is formed so as to cover the display region 103. Theinorganic sealing layer 162 may be formed by plasma CVD, thermal CVD,vapor deposition, spin-coating, spraying or printing. For example, theinorganic sealing layer 162 may be formed of a silicon nitride film byplasma CVD.

Next, the organic sealing layer 163 is formed on the inorganic sealinglayer 162 (see FIG. 6A and FIG. 6B). An organic layer to be the organicsealing layer 163 is formed by spin-coating, vapor deposition, spraying,ink-jetting, printing or the like to a thickness of about severalmicrometers to about several ten micrometers, and then is processed by,for example, photolithography and dry etching. Thus, the organic sealinglayer 163 is formed. It is preferable that the organic sealing layer 163is formed such that the edge thereof is located between the edge of thedisplay region 103 and the edge of the inorganic sealing layer 162. Themethod for forming the organic sealing layer or the method forprocessing the organic sealing layer is not limited to the above and maybe optionally changed.

Next, the organic sealing layer 165 is formed on the organic sealinglayer 163 (see FIG. 7A and FIG. 7B). The organic sealing layer 165 isformed in substantially the same method as that of the organic sealinglayer 163. It is preferable that the organic sealing layer 165 is formedsuch that the edge thereof is located between the edge of the organicsealing layer 163 and the edge of the display region 103.

Next, the organic sealing layer 167 is formed on the organic sealinglayer 165, the organic sealing layer 163 and the inorganic sealing layer162 (see FIG. 8A and FIG. 8B). The organic sealing layer 167 is formedin substantially the same method as that of the organic sealing layer163. It is preferable that the organic sealing layer 167 is formed suchthat the edge thereof is located between the edge of the organic sealinglayer 163 and the edge of the inorganic sealing layer 162.

Next, the inorganic sealing layer 169 is formed on the organic sealinglayer 167 and the inorganic sealing layer 162 (see FIG. 9A and FIG. 9B).The inorganic sealing layer 169 may be formed in substantially the samemethod as that of the inorganic sealing layer 162. The edges of theinorganic sealing layer 162 and the inorganic sealing layer 169 arelocated outer to any of the edges of the display region 103, the organicsealing layer 163, the organic sealing layer 165 and the organic sealinglayer 167. Such an arrangement of the inorganic sealing layer 162 andthe inorganic sealing layer 169 may be realized by use of a mask or withno use of a mask.

The inorganic sealing layer 164 may be formed after the organic sealinglayer 163 is formed but before the organic sealing layer 165 is formed.The inorganic sealing layer 166 may be formed after the organic sealinglayer 165 is formed but before the organic sealing layer 167 is formed.

Next, a conductive layer 170, which is to be the conductive layer 171,is formed on the inorganic sealing layer 169. The conductive layer 170may be formed by sputtering, CVD, vapor deposition or the like.

Next, a photoresist 172 is formed on the conductive layer 170 (see FIG.10A and FIG. 10B). It is preferable that as shown in FIG. 10B, thephotoresist 172 is formed to be wider in the area thereof overlappingthe edges of the organic sealing layer 163, the organic sealing layer165 and the organic sealing layer 167 than in the remaining area. Thearea of the photoresist 172 overlapping the edges of the organic sealinglayer 163, the organic sealing layer 165 and the organic sealing layer167 may be as wide as the remaining area. It is preferable that thewidth of the photoresist 172 in the area corresponding to the edges isequal to or more than, and at most twice, the width of the photoresist172 in the remaining area.

Next, the conductive layer 170 is dry-etched to form the conductivelayer 171. The conductive layer 170 is likely to be etched more thannecessary in an area thereof overlapping steps provided by the edges ofthe organic sealing layer 163, the organic sealing layer 165 and theorganic sealing layer 167 because the photoresist 172 is thinner in thisarea. The photoresist 172 is formed to be wider in this area asdescribed above, so that the width of the post-etching conductive layer170 is not smaller in this area than in the remaining area. Regardingthe photoresist 172 having such a wider area, it is not necessary tocontrol the shape of the photoresist 172 precisely. It is sufficientthat the photoresist 172 has a sufficient width after the etching and isnot short-circuited with the other lines. It causes no problem even ifthe post-etching conductive layer 170 is still wider or is slightlythinner in this area than in the remaining area. Next, the sealingmember 173 and the filling member 174 are formed (see FIG. 11A and FIG.11B). The sealing member 173 and the filling member 174 may be formed byspin-coating, vapor deposition, spraying, ink-jetting, printing or thelike.

The above-described manufacturing method allows the display device 10 tobe manufactured stably with a higher level of sealing property withoutbreaking the lines for the touch sensor.

The structure, method or the like described in embodiment 3 may beappropriately combined with a structure, method or the like shown in anyother embodiment.

(Embodiment 4, Display Device Structure 2)

Hereinafter, a structure including the other components of the displaydevice 10 will be described with reference to the drawings.

FIG. 12 is a cross-sectional view of the display device 10. Morespecifically, FIG. 12 shows a cross-section of the peripheral region 104taken along line A1-A2 in FIG. 1A, a cross-section of a pixel regionincluding one pixel 102 taken along line B1-B2 in FIG. 1A, across-section of a driving circuit region including the driving circuit107 taken along line C1-C2 in FIG. 1A, and a cross-section of a terminalregion including the driving circuit 106 taken along line D1-D2 in FIG.1A. FIG. 12 shows the structure of the display device 10 in the casewhere the sealing layer 161 has the structure shown in FIG. 1B. FIG. 13shows the structure of the display device 10 in the case where thesealing layer 161 has the structure shown in FIG. 2A. (Hereinafter, theperipheral region 104 may be referred to as the “peripheral region A1-A2region”, the pixel region may be referred to as the “pixel regionB1-B2”, the driving circuit region may be referred to as the “drivingcircuit region C1-C2”, and the terminal region may be referred to as the“terminal region D1-D2”.)

A transistor 110 and a transistor 111 each include a semiconductor layer142, a gate insulating layer 143, a gate electrode layer 145, asource/drain electrode layer 147, and the like. In FIG. 12, thetransistors 110 and 111 each have a top gate/top contact structure. Thetransistors 110 and 111 are not limited to having such a structure, andmay each have a bottom gate structure or a bottom contact structure. Inthe case where the transistors 110 and 111 each have both of an nchannel and a p channel, the transistors 110 and 111 may each have aCMOS structure so as to increase the degree of integration and alsorealize low power consumption.

The substrates 100 and 101 are formed of glass or an organic resinmaterial. A usable organic resin material is, for example, polyimide.The substrates 100 and 101, when being formed of an organic resinmaterial, may each have a thickness of several micrometers to severalten micrometers, so that the display device 10 is a flexible sheetdisplay. The substrate 100 or 101 needs to be transparent in order toallow light emitted by a light emitting element (described below) to beoutput outside the display device 10. A substrate on the side from whichlight is not output does not need to be transparent, and therefore, maybe formed of a metal substrate and an insulating film formed on asurface of the metal substrate, instead of being formed of theabove-described material. The display device 10 may include a glasscover, a protective film or the like provided on each of second surfacesof the substrates 100 and 101 (namely, outer surfaces of the substrates100 and 101 as seen in a cross-sectional view). The glass cover, theprotective film or the like protects the display device 10 againstscratches, breakage or the like. The substrate 101 has a role ofprotecting the light emitting element (described below), but does notneed to have such a function if the sealing layer 161 sufficientlyprotects the light emitting element.

An insulating layer 141 acts as an underlying layer. The insulatinglayer 141 may be formed of silicon oxide, silicon oxide nitride, siliconnitride, silicon nitride oxide, gallium oxide, hafnium oxide, yttriumoxide, aluminum oxide, aluminum oxide nitride, or the like. Theinsulating layer 141 may be a single layer or may be a stack of aplurality of layers. The insulating layer 141 may be formed of any ofthe above-described materials, so as to suppress impurities, typically,an alkaline metal material, water, hydrogen or the like from beingdiffused from the substrate 100 into the semiconductor layer 142.

The semiconductor layer 142 may be formed of silicon, silicon germanium,an oxide semiconductor, an organic semiconductor or the like. Examplesof usable type of silicon include amorphous silicon, microcrystallinesilicon, polycrystalline silicon, single crystalline silicon, and thelike. Usable as an oxide semiconductor is at least one metal materialamong indium, gallium, zinc, titanium, aluminum, tin, hafnium,neodymium, zirconium, lanthanum, cerium and yttrium. The semiconductorlayer 142 may be formed of an oxide semiconductor containing indium,gallium and zinc (IGZO).

The gate insulating layer 143 may be formed of an insulating materialcontaining at least one of aluminum oxide, magnesium oxide, siliconoxide, silicon oxide nitride, silicon nitride oxide, silicon nitride,gallium oxide, zirconium oxide, lanthanum oxide, neodymium oxide,hafnium oxide and tantalum oxide.

The insulating layer 149 and an insulating layer 154 may each be formedof any of the above-described materials usable for the gate insulatinglayer 143. The insulating layer 149 and the insulating layer 154 mayeach be a single layer or may be a stack of a plurality of layers.

The gate insulating layer 145 and the source/drain electrode layer 147may each be formed of a metal element selected from tungsten, aluminum,chromium, copper, titanium, tantalum, molybdenum, nickel, iron, cobalt,indium and zinc, an alloy containing any of the above-listed metalmaterials as one component, an alloy obtained as a result of combiningany of the above-listed metal materials, or the like. The gate electrodelayer 145 and the source/drain electrode layer 147 may each containnitrogen, oxygen, hydrogen or the like. The gate insulating layer 145and the source/drain electrode layer 147 may each be a stack of any ofthe above-listed materials.

An insulating layer 150 acts as a planarization film. The insulatinglayer 150 may be formed of an organic insulating material, an inorganicinsulating material, or an insulating material containing an organicinsulating material and an inorganic insulating material in a stackingmanner. The insulating layer 150 may be formed of, for example, a filmcontaining silicon oxide, silicon nitride or the like, a polymermaterial such as acrylic resin, polyester, polyamide, polyimide,polysiloxane or the like, or a photosensitive resin.

A conductive layer 153 may be formed of any of substantially the samematerials as those usable for the gate electrode layer 145 and thesource/drain electrode layer 147.

A capacitance element 120 may be provided in a region where a source ordrain region of the semiconductor layer 142, and a capacitance electrodelayer 146 formed of any of substantially the same materials as thoseusable for the gate electrode layer 145, overlap each other while havingthe gate insulating layer 143 acting as a dielectric layer therebetween.A capacitance element 121 may be provided in a region where thecapacitance electrode layer 146 and a capacitor electrode layer 148 a,which is formed of any of substantially the same materials as thoseusable for the source/drain electrode layer 147, overlap each otherwhile having the insulating layer 149 acting as a dielectric layertherebetween. A capacitance element 122 may be provided in a regionwhere the conductive layer 153 and a conductive layer 155 overlap eachother while having the insulating layer 154 acting as a dielectric layertherebetween.

The light emitting element 130 may include the conductive layer 155, anorganic EL layer 159 and the conductive layer 160. In an embodimentaccording to the present invention, the light emitting element 130 has aso-called top emission structure, in which light emitted by the organicEL layer 159 is output toward the conductive layer 160. The lightemitting element 130 is not limited to having a top emission structure,and may have a bottom emission structure.

The organic EL layer 159 contains a light emitting material such as anorganic electroluminescence material or the like. The organic EL layer159 may be formed of a low molecular weight-type or high molecularweight-type organic material. In the case of being formed of a lowmolecular weight-type material, the organic EL layer 159 may include alight emitting layer containing a light emitting organic material andalso include a hole injection layer and an electron injection layer ormay further include a hole transfer layer and an electron transferlayer. The hole injection layer and the electron injection layer, or thehole transfer layer and the electron transfer layer, when beingincluded, are provided so as to have the light emitting layertherebetween. For example, the organic EL layer 159 may have a structurein which the light emitting layer is held between the hole injectionlayer and the electron injection layer. The organic EL layer 159 mayfurther include the hole transfer layer, the electron transfer layer, ahole block layer, an electron block layer and the like as necessary, inaddition to the hole injection layer and the electron injection layer.

The conductive layer 155 preferably has a function of a pixel electrodeand also has a light reflecting property. The conductive layer 155 maybe formed of, for example, a light reflective metal material such asaluminum (Al), silver (Ag) or the like. Alternatively, the conductivelayer 155 may have a structure including a transparent conductive layerformed of ITO (indium tin oxide; tin oxide-containing indium oxide) orIZO (indium zinc oxide; indium oxide-zinc oxide) and a light reflectivemetal layer in a stacking manner.

The conductive layer 160 may be formed of a transparent conductive filmsuch as ITO, IZO or the like, which is light transmissive so as to allowlight emitted in the organic EL layer 159 to be transmitted through theconductive layer 160, and is also conductive.

The conductive layer 171 has a function of a line for the touch sensor.The conductive layer 171 may be formed of any of substantially the samematerials as those usable for the conductive layer 160. In the casewhere the conductive layer 171 is a microscopic line, the conductivelayer 171 may be formed of any of the above-described materials usablefor the gate electrode layer 145 and the source/drain electrode layer147. In the case where the conductive layer 171 is formed of any ofsubstantially the same material as those usable for the source/drainelectrode layer 147, the conductivity of the conductive layer 171 isimproved. This allows the touch sensor to respond at high speed.

A bank layer 157 is formed of an organic resin material to cover aperiphery of the conductive layer 155 and to form a smooth step at anedge of the conductive layer 155. Usable organic resin materials includeacrylic resin, polyimide and the like.

The sealing member 173 and the filling member 174 are each formed of aninorganic material, an organic material, or a composite material of anorganic material and an inorganic material. The sealing member 173 andthe filling member 174 may each be formed of, for example, epoxy resin,acrylic resin, silicone resin, phenol resin, polyimide resin, imideresin, silica gel or the like.

A color filter layer 175 has a function of transmitting light of aspecific wavelength range. The color filter layer 175 transmits lightof, for example, a red, green, blue or yellow wavelength range. In thecase where light emitted from the organic EL layer 159 has differentcolors on a pixel-by-pixel basis, the color filter layer 175 may not beneeded.

A light blocking layer 177 has a function of blocking light. The lightblocking layer 177 may be formed of, for example, a resin containing apigment dispersed therein, a dye-containing resin, an inorganic materialsuch as black chromium or the like, carbon black, a composite oxidecontaining solid-solution of a plurality of inorganic oxides, or thelike.

The flexible printed circuit board 108 may be electrically connectedwith the capacitor electrode layer 148 a via an anisotropic conductivefilm 181.

The structure, method or the like described in embodiment 4 may beappropriately combined with a structure, method or the like shown in anyother embodiment.

(Embodiment 5, Method for Manufacturing the Display Device)

Hereinafter, a method for manufacturing the display device 10 will bedescribed with reference to FIG. 14 to FIG. 17.

(5-1. Formation of the Transistors and Inter-layer Insulating Layer)

As shown in FIG. 14, the following components are formed on a firstsurface (upper surface as seen in a cross-sectional view) of thesubstrate 100: the insulating layer 141, the transistor 110 in the pixelregion B1-B2 (the transistor 110 is formed so as to include thesemiconductor layer 142, the gate insulating layer 143 and the gateelectrode layer 145), the capacitance element 120 (formed to include thecapacitance electrode layer 146, the gate insulating layer 143, and thesource/drain region of the semiconductor layer 142), the transistor 111in the driving circuit region C1-C2, the capacitance element 121 (formedto include the capacitance electrode layer 146, the insulating layer149, and the capacitor electrode layer 148 a), the source/drainelectrode layer 147, a terminal layer (conductive layer) 148 b in theterminal region D1-D2, the insulating layer 149, and the insulatinglayer 150. The transistor 110 in the pixel region B1-B2 and thetransistor 111 in the driving circuit region C1-C2 have the samestructure with each other. The capacitor electrode layer 148 a and theterminal layer 148 b in the terminal region D1-D2 are formed on theinsulating layer 149 and formed by the same conductive layer as thesource/drain electrode layer 147. As the source/drain electrode layer147, a stack of three layers, specifically, a titanium (Ti) layer, analuminum (Al) layer and a titanium (Ti) layer provided in this orderfrom the lower side may be formed. Each of these layers may beappropriately formed by photolithography, nanoimprinting, ink-jetting,etching or the like so as to have a predetermined shape.

Referring to FIG. 14, the insulating layer 149 may be a single layer ora stack of a plurality of layers. The insulating layer 149 is formed by,for example, stacking a silicon nitride film and a silicon oxide film.The insulating layer 149 is formed by CVD (plasma CVD or thermal CVD),sputtering or the like. The insulating layer 150 on the insulating layer149 is formed of an organic insulating material. The organic insulatinglayer preferably contains a polymer material such as polyester,polyamide, polyimide, polysiloxane or the like. The insulating layer 150of such an organic insulating material is formed on generally theentirety of the surface of the substrate 100 by spin-coating,ink-jetting, laminating, printing, dip-coating, vapor depositionpolymerization or the like. The insulating layer 150 is preferablyformed to have a thickness of 1 μm or greater. With such a thickness,the insulating layer 150 compensates for concaved and convexed portionsprovided by the transistor 110 or the like to provide a flat surfaceabove the substrate 100.

(5-2. Formation of the Light Emitting Element)

Next, as shown in FIG. 15, the following components are formed on theinsulating layer 150 in the pixel region B1-B2: the capacitance element122 (formed to include the conductive layer 153, the insulating layer154, and the conductive layer 155), the light emitting element 130(formed to include the conductive layer 155, the organic EL layer 159,and the conductive layer 160), and the bank layer 157. Each of thecomponents may be appropriately formed by photolithography,nanoimprinting, ink-jetting, etching or the like so as to have apredetermined shape.

The conductive layer 153 and the conductive layer 155 may be formed bysputtering, vapor deposition, plating or the like to have a thickness ofseveral ten nanometers to several hundred nanometers. For example, theconductive layer 153 may be formed by stacking molybdenum, aluminum andmolybdenum by use of sputtering. The conductive layer 155 may be formedby, for example, stacking ITO, silver and ITO by use of sputtering.

The insulating layer 154 may be formed of CVD (plasma DVD or thermalCVD), spin-coating, printing or the like. For example, the insulatinglayer 154 may be formed of silicon nitride by plasma CVD.

The bank layer 157 is formed to have an opening exposing an uppersurface of the conductive layer 155. An edge of the opening of the banklayer 157 preferably has a smooth tapering shape. This improves the stepcoverage. The bank layer 157 may be formed so as not to be on an uppersurface of the conductive layer 148 b in the terminal region D1-D2, ormay be formed to have an opening exposing the upper surface of theconductive layer 148 b. The bank layer 157 may be formed to have athickness of several micrometers. The bank layer 157 may be formed ofpolyimide by spin-coating.

The organic EL layer 159 is preferably formed to at least overlap theconductive layer 155. The organic EL layer 159 is formed by, forexample, vacuum vapor deposition, printing, spin-coating or the like. Inthe case of being formed by vacuum vapor deposition, the organic ELlayer 159 is preferably formed by use of a shadow mask so as not to bein the terminal region D1-D2. The organic EL layer 159 may be formed ofdifferent materials among pixels adjacent to each other, or may beformed of the same material in all the pixels. In the case where theorganic EL layer 159 outputting white light is formed so as to beincluded in all the pixels, the color filter 175 or the like may beused, so that light of different colors is output from different pixels.

After the organic EL layer 159 is formed, the conductive layer 160 isformed. The conductive layer 160 is formed of a light transmissiveconductive material by sputtering. In the case where, for example, thelight emitting element 130 is of a top emission type, by which light isoutput from the conductive layer 160, the conductive layer 160preferably has a uniform thickness.

The conductive layer 160 may be formed by vacuum vapor deposition orsputtering. The conductive layer 160 may not be formed in the terminalregion D1-D2, or may be removed from the terminal region D1-D2 afterbeing formed. The conductive layer 160 may be formed of IZO bysputtering.

(5-3. Formation of the Sealing Layer)

Next, as shown in FIG. 16, the sealing layer 161 and the conductivelayer 171 are formed on the conductive layer 160. The formation of thesealing layer 161 is described in embodiment 3 and will not be describedhere.

The peripheral region A1-A2 includes a region where the insulating layer140 and the bank layer 157 have been removed. The insulating layer 154is formed on a side surface of the insulating layer 150 and also on anupper surface of the insulating layer 149. The conductive layer 160 isformed on a side surface of the bank layer 157 and also on an uppersurface of the insulating layer 154.

As described above, the peripheral region A1-A2 includes a region inwhich the insulating layer 150 and the bank layer 157, which are formedof an organic insulating material, have been removed, and in which theinsulating layer 154 and the conductive layer 160, which are formed ofan inorganic material, are formed. With such a structure, the insulatinglayer 150 and the bank layer 157, which are formed of an organicinsulating material, are held between the layers each formed of aninorganic material. This structure prevents permeation of moisture orthe like from the peripheral region A1-A2 into the pixel region B1-B2.The combination of the inorganic insulating layer 162 and the inorganicinsulating layer 169 included in the sealing layer 161 in an embodimentaccording to present invention further enhances the moisture blockingeffect. Therefore, the above-described region acts as a moistureblocking region 179, and the structure thereof may be considered as a“moisture blocking structure”.

(5-4. Bonding of the Above-described Structure with a Counter Substrate,Joining of the Flexible Printed Circuit Board)

Next, as shown in FIG. 17, the color filter layer 175 and the lightblocking layer 177 are formed on the substrate 101, which acts as acounter substrate. Then, the substrate 101 and the substrate 100 arebonded together with the sealing member 173 and the filling member 174.

The light blocking layer 177 may be formed by spin-coating, spraying orink-jetting. The light blocking layer 177 may be formed to have anopening in a region in the pixel region B1-B2 where light from the lightemitting element 130 is output. For example, the light blocking layer177 may be formed of a photosensitive organic resin containing a blackpigment (i.e., formed of a black resist) by spin-coating.

The color filter layer 175 is formed, by printing, ink-jetting, etchingusing photolithography or the like, in the region in the pixel regionB1-B2 where the light from the light emitting element 130 is output.

Before the substrate 100 and the substrate 101 are bonded together withthe sealing member 173 and the filling member 174, a spacer or the likemay be provided in advance in order to stabilize the distance betweenthe substrate 100 and the substrate 101. The spacer may be formed ofeither an organic insulating material or an inorganic insulatingmaterial. In the case where the filling member 174 is formed of aphotocurable adhesive, the filling member 174 is cured quickly and thusthe work time is shortened.

The flexible printed circuit board 108 may be electrically connectedwith the conductive layer 148 b by use of the anisotropic conductivefilm 181. At this point, it is preferable that the insulating layersincluded in the sealing film 161 (i.e., the inorganic insulating layer162, the organic insulating layer 163, the organic insulating layer 165,and the inorganic insulating layer 169) may be removed from the terminalregion D1-D2 by laser radiation or the like. The anisotropic conductivefilm 181 may be formed by application of a resin containing metalparticles such as silver particles, copper particles or the like.

With the manufacturing method in the above-described embodiment, adisplay device having a high level of barrier property against moistureand also include a touch sensor having a stable shape is manufactured.

The structure, method or the like described in embodiment 5 may beappropriately combined with a structure, method or the like shown in anyother embodiment.

What is claimed is:
 1. A display device, comprising: a display regionincluding a plurality of light emitting elements arrayed in a matrix; afirst inorganic insulating layer covering the plurality of lightemitting elements; a first organic insulating layer on the firstinorganic insulating layer; a second organic insulating layer on thefirst organic insulating layer; a third organic insulating layer on thesecond organic insulating layer; and a second inorganic insulating layeron the third organic insulating layer, wherein an edge of the firstorganic insulating layer, an edge of the second organic insulatinglayer, and an edge of the third organic insulating layer are locatedbetween an edge of the first inorganic insulating layer and the displayregion, the edge of the second organic insulating layer is locatedbetween the edge of the first organic insulating layer and the displayregion, the edge of the first organic insulating layer is locatedbetween the edge of the second organic insulating layer and the edge ofthe third organic insulating layer, the third organic insulating layercovers the edge of the first organic insulating layer and the edge ofthe second organic insulating layer, and the edges of the firstinorganic insulating layer and the second inorganic insulating layer arelocated outer to the edge of the display region and the edges of thefirst to third organic insulating layers.
 2. The display deviceaccording to claim 1, wherein the first inorganic insulating layer andthe second inorganic insulating layer are in contact with each other ata position outer to the edge of the third organic insulating layer. 3.The display device according to claim 1, further comprising: a thirdinorganic insulating layer between the first organic insulating layerand the second organic insulating layer; and a fourth inorganicinsulating layer between the second organic insulating layer and thethird organic insulating layer.
 4. The display device according to claim1, wherein the edges of the first to third organic insulating layers aretapered.
 5. The display device according to claim 1, wherein the edgesof the first to third organic insulating layers each have a roundedshape in a cross-sectional view.
 6. The display device according toclaim 1, further comprising: a line layer on the second inorganicinsulating layer, the line layer extending from the display region to aposition outer to the third organic insulating layer, wherein the linelayer has a first line width in an area thereof overlapping the displayregion and has a second line width greater than the first line width inan area thereof overlapping the edges of the first to third organicinsulating layers.